Inflation apparatus for an inflation-based non-invasive blood pressure monitor and a method of operating the same

Abstract

According to an aspect there is provided an inflation apparatus (10) for use with an inflation-based non-invasive blood pressure, NIBP, measurement apparatus, the inflation apparatus comprising: an outlet (110) configured to be coupled to a cuff of the inflation-based NIBP measurement apparatus; a pump (120) configured to output a flow of gas at an output flow rate; a valve (130) disposed along a flow path between the pump and the outlet to selectively pass part of the flow of gas output by the pump; and a control unit (140) configured to control the flow resistance of the valve to provide a flow of gas to the outlet at a required flow rate for inflating the cuff.

The invention claimed is: 
     
         1 . An inflation apparatus for use with an inflation-based non-invasive blood pressure (NIBP) measurement apparatus, the inflation apparatus comprising:
 an outlet configured to be coupled to a cuff of the inflation-based NIBP measurement apparatus;   a pump configured to output a flow of gas at an output flow rate;   a valve disposed along a flow path between the pump and the outlet to selectively pass part of the flow of gas output by the pump to the atmosphere during inflation of the cuff; and   a processor configured to: control a flow resistance of the valve to provide a flow of gas to the outlet at a required output flow rate for inflating the cuff, wherein the control of the flow resistance comprises determining when the flow of gas is lower than a minimum output flow rate of the pump, and determining the required output flow rate of the pump so that the flow of gas at the outlet is at the required flow rate for inflating the cuff.   
     
     
         2 . The inflation apparatus according to  claim 1 ,
 wherein the valve is a leak valve, and   the processor is further configured to control: (i) a switching of the leak valve, and (ii) the pump to adjust the output flow rate of the pump to provide a flow of gas to the outlet at the required flow rate.   
     
     
         3 . The inflation apparatus according to  claim 2 , wherein the processor is further configured to open the leak valve when the required flow rate is lower than the minimum flow rate of the pump, so as to pass a part of the flow of gas output by the pump to the atmosphere. 
     
     
         4 . The inflation apparatus according to  claim 2 , wherein the processor is further configured to open the leak valve based on the compliance value, so as to pass a part of the flow of gas output by the pump to the atmosphere. 
     
     
         5 . The inflation apparatus according to  claim 1 ,
 wherein the valve is a proportional valve that is configured to pass a part of the flow of gas output by the pump to the atmosphere when the proportional valve is opened, and   wherein the processor is further configured to control the flow resistance of the proportional valve to provide a flow of gas to the outlet at the required flow rate.   
     
     
         6 . The inflation apparatus according to  claim 5 , wherein the processor is further configured to:
 control the flow resistance of the proportional valve so as to provide a flow of gas to the outlet at the required flow rate.   
     
     
         7 . The inflation apparatus according to  claim 5 , wherein the processor is further configured to open the proportional valve based on the compliance value, so as to pass a part of the flow of gas output by the pump to the atmosphere. 
     
     
         8 . The inflation apparatus according to  claim 5 , wherein the output flow rate of the pump is fixed. 
     
     
         9 . The inflation apparatus according to  claim 5 , wherein the processor is further configured to control the pump to adjust the output flow rate of the pump. 
     
     
         10 . The inflation apparatus according to  claim 1 , wherein the required flow rate is determined based on at least one of a rate of change of pressure in the cuff and the compliance value. 
     
     
         11 . The inflation apparatus according to  claim 1 , further comprising a release valve in fluid communication with the inflatable cuff for selectively deflating the cuff. 
     
     
         12 . An inflation-based non-invasive blood pressure (NIBP) measurement apparatus comprising:
 an inflation apparatus comprising:
 an outlet configured to be coupled to a cuff of the inflation-based NIBP measurement apparatus; 
 a pump configured to output a flow of gas at an output flow rate; 
   a valve disposed along a flow path between the pump and the outlet to selectively pass part of the flow of gas output by the pump to the atmosphere during inflation of the cuff;   a processor configured to: control a flow resistance of the valve to provide a flow of gas to the outlet at a required output flow rate for inflating the cuff based on a compliance value measured before or during the inflation of the cuff, wherein the control of the flow resistance comprises determining when the flow of gas is lower than a minimum output flow rate of the pump, and determining the required output flow rate of the pump so that the flow of gas at the outlet is at the required flow rate for inflating the cuff; and   a sensor configured to measure arterial oscillations in a body part of a subject when, in operation, the cuff is positioned around the body part, with the cuff being coupled to the outlet of the inflation apparatus and being inflated by the inflation apparatus;   wherein the processor is a processor of the inflation apparatus or a processor in the inflation-based NIBP measurement apparatus is configured to receive measurements of arterial oscillations from the sensor and to determine the blood pressure of the subject based on the received measurements.   
     
     
         13 . A method of controlling an inflation apparatus for use with an inflation-based non-invasive blood pressure (NIBP) measurement apparatus, the method comprising:
 outputting, via a pump, a flow of gas at an output flow rate;   selectively passing part of the flow of gas output to the atmosphere during inflation of a cuff of the inflation-based NIBP measurement apparatus via a valve disposed along a flow path between the pump and an outlet, wherein the outlet is configured to be coupled to the cuff of the inflation-based NIBP measurement apparatus; and   controlling, via a processor, a flow resistance of the valve to provide a flow of gas to the outlet at a required output flow rate for inflating the cuff, wherein the control of the flow resistance comprises determining when the flow of gas is lower than a minimum output flow rate of the pump, and determining the required output flow rate of the pump so that the flow of gas at the outlet is at the required flow rate for inflating the cuff.   
     
     
         14 . A tangible, non-transitory computer readable medium comprising computer readable code, which when executed by a processor, causes the processor to:
 control a flow resistance based on a compliance value measured before or during inflation of a cuff to provide a flow of gas between a pump and an outlet at a required flow rate to inflate a cuff via a valve disposed along a flow path between the pump and the outlet, wherein the control of the flow resistance comprises determining when the flow of gas is lower than a minimum output flow rate of the pump, and determining the required output flow rate of the pump so that the flow of gas at the outlet is at the required flow rate for inflating the cuff.   
     
     
         15 . The tangible, non-transitory computer readable medium of  claim 14 , wherein: the valve is a leak valve that is configured to pass a part of a flow of gas output by the pump to the atmosphere when the leak valve is opened; a flow resistance of the leak valve is fixed; and the computer readable code, when executed by the processor further causes the processor to control: (i) a switching of the leak valve, and (ii) the pump to adjust an output flow rate of the pump to provide a flow of gas to the outlet at the required flow rate. 
     
     
         16 . The tangible, non-transitory computer readable medium of  claim 15 , wherein computer readable code, when executed by the processor further causes the processor to open the leak valve when the required flow rate is lower than the minimum flow rate of the pump, to pass a part of the flow of gas output by the pump to the atmosphere. 
     
     
         17 . The tangible, non-transitory computer readable medium of  claim 15 , wherein computer readable code, when executed by the processor further causes the processor to open the leak valve based on the compliance value, so as to pass a part of the flow of gas output by the pump to the atmosphere. 
     
     
         18 . The tangible, non-transitory computer readable medium of  claim 14 , wherein:
 the valve is a proportional valve that is configured to pass a part of a flow of gas output by the pump to the atmosphere when the proportional valve is opened, and   the computer readable code further causes the processor to control the flow resistance of the proportional valve to provide a flow of gas to the outlet at the required flow rate.   
     
     
         19 . The tangible, non-transitory computer readable medium of  claim 18 , wherein computer readable code, when executed by the processor further causes the processor to:
 control the flow resistance of the proportional valve so as to provide a flow of gas to the outlet at the required flow rate.   
     
     
         20 . The tangible, non-transitory computer readable medium of  claim 18 , wherein computer readable code, when executed by the processor further causes the processor to open the proportional valve based on the compliance value, to pass a part of the flow of gas output by the pump to the atmosphere.